Two serious vulnerabilities exist in phpMyAdmin. The first allows any
user to alter the server configuration variables (including host, name,
and password) by appending new settings to the array variables that
hold the configuration in a GET statement. The second allows users to
include arbitrary PHP code to be executed within an eval() statement in
table name configuration settings. This second vulnerability is only
exploitable if $cfg['LeftFrameLight'] is set to FALSE.

Impact

Authenticated users can alter configuration variables for their running
copy of phpMyAdmin. The impact of this should be minimal. However, the
second vulnerability would allow an authenticated user to execute
arbitrary PHP code with the permissions of the webserver, potentially
allowing a serious Denial of Service or further remote compromise.

Workaround

The second, more serious vulnerability is only exploitable if
$cfg['LeftFrameLight'] is set to FALSE. In the default Gentoo
installation, this is set to TRUE. There is no known workaround for the
first.